1. Field of the Invention
The present invention generally relates to a current detecting and indicating device and, more particularly, to a current detecting and indicating device having a plurality of magnetic reed switches with different current levels for detecting abnormal currents of a power distribution system.
2. Description of the Related Art
A conventional current detecting and indicating device is used to detect whether an abnormal current occurs on any part of a power distribution system. The detected result is then provided to a person monitoring the operation condition of the power distribution system. However, the conventional current detecting and indicating device can only show the person which specific part of the power distribution system the abnormal current has taken place rather than showing a magnitude of the abnormal current. To show the specific magnitude of the abnormal current, an expensive current sensor and a high performance micro processor should be used. However, it is not economical to use that many devices in a wide-ranging power distribution system.
Taiwan Patent Numbers 1263050 and 517420 disclose a power distribution system that uses a current transformer, a measurement circuit and a digital display device for detecting an abnormal current. In the power distribution, although the magnitude of the abnormal current may be shown by the digital display device, it is still not economical to use such expensive devices in the wide-ranging power distribution system.
Furthermore, U.S. Pat. No. 7,615,988 discloses a wide range current detecting method and system, which use a plurality of transformer coils for detecting currents by way of induction. In such a mechanism, it is also required to use a current transformer. Besides, the transformer coils also require a measurement circuit and a display device for current detection. Thus, cost is increased.
Therefore, it is desired to improve the conventional current detecting and indicating device.